Nanoparticles are nanometer-sized materials e.g., metals, semiconductors, polymers, organics, and the like, that can often posses unique characteristics because of their small size. Polymer nanoparticles of pharmaceutical or crop protection active ingredients (Als) are of particular interest because of the potential for reduced use of formulants, improved bioavailability, modified translocation, or controlled release properties. Polymer nanoparticles with hollow interiors have found widespread use in many applications such as controlled release of drugs of pharmaceuticals, active ingredients (Als) in agriculture, cosmetics, and foods. They are also found to protect biologically active species from degradation, and can be used remove pollutants from the environment.